Hey, Mr. President: lay off Jeff Sessions!

President Trump is doing himself no favors with his non-stop public humiliation and belittling of Attorney General Jeff Sessions.

The prez this week launched his latest Twitter broadside against Sessions, calling it “DISGRACEFUL!” that the AG intends to have the Justice Department’s inspector general investigate possible abuse of Foreign Intelligence Surveillance Act wiretaps.

Trump objects because IG Michael Horowitz is “an Obama guy.”

Yes, the last president appointed Horowitz — but he’s a highly regarded career prosecutor who’s served in administrations of both parties. Besides, the law says the IG is supposed to handle allegations of internal misconduct, and Horowitz’s past probes have zinged some of the very FBI and Justice Department officials that Trump regularly complains about.

Sessions, in short, is doing his job — and doing it by the book, as he has all along.

But Trump has been targeting his attorney general ever since he recused himself from the Russia investigation, leading to the appointment of Robert Mueller.

He has demanded Sessions’ resignation, publicly attacked him for not investigating Hillary Clinton’s “crimes” and reportedly called him an “idiot” in private.

At best, this is monumental ingratitude: Sessions was the first senator to endorse Trump and provided vital help on issues during the primaries. And he has unwaveringly backed Trump and his agenda.

In rare public pushback to the “disgraceful” tweet, Sessions issued a statement making clear he intends to “discharge my duties with integrity and honor” and pledging the department will work “in a fair and impartial manner.”

Which is precisely the point: The attorney general — unlike the White House counsel — isn’t there to protect the president’s behind and run interference for him.

Trump needs to accept that, and stop treating Sessions like a contestant on “The Apprentice.” It’s undignified and bad for the country. Back off, Mr. President.